An example of a short-range wireless communication antenna for in-vehicle communication is a Bluetooth antenna for Bluetooth communication. Bluetooth is a registered trademark.
In one type of in-vehicle Bluetooth communication system, the Bluetooth antenna and a Bluetooth module including a high frequency circuit, a signal processing circuit, and a power supply circuit are mounted on a single circuit board, and thus assembled as a Bluetooth sub-assembly. The Bluetooth sub-assembly is built in an in-vehicle display.
In another type of in-vehicle Bluetooth communication system, the Bluetooth antenna is separated from the Bluetooth module and mounted behind a front wall of an instrument panel of a vehicle to ensure adequate performance of the Bluetooth antenna. This type is generally used when the vehicle has no in-vehicle display.
As described above, the manner in which the Bluetooth antenna is mounted to the vehicle depends on whether the vehicle has the in-vehicle display. Further, the manner needs to be changed depending on shape and material of equipment of the vehicle in order to prevent a metal part of the vehicle from affecting the Bluetooth antenna. Therefore, the manner varies from one type of vehicle to another.
Recently, there has been an increased demand for short-range wireless communication (e.g., hands free communication) in the vehicle. In view of the increased demand, an increase in development time and design time of the in-vehicle Bluetooth communication system may be caused by the fact that the manner in which the Bluetooth antenna is mounted to the vehicle varies from one type of vehicle to another. Accordingly, manufacturing cost of the in-vehicle Bluetooth communication system may be increased.
In a touch panel display disclosed in JP-A-2003-280815, a microstrip antenna is mounted to an upper electrode plate of the display. However, this approach cannot overcome the problem of the increase in the development time, the design time, and the manufacturing cost.